1. Field of the Invention
The present invention relates to a transmitter having a power amplifier for transmitting a modulated carrier signal.
2. Description of the Prior Art
This kind of transmitter is hitherto composed as disclosed in U.S. Pat. No. 4,933,986. In this prior art, the transmission signal sent from the transmitter is received by the same transmitter and demodulated to produce a baseband feedback signal, and this signal is applied to a modulation baseband signal. By controlling in such a feedback loop, distortion of the power amplifier is compensated for. This approach, however, involves several disadvantages. First, the device size is increased because the receiver and demodulator are necessary for producing the baseband feedback signal. Further, gain fluctuations of the receiver and demodulator induce variations of the transmission output, and the complicatedness of this part still worsens the problem.